Stainless steel hinges rust?

This problem believes that many friends will not believe, we will feel that "stainless steel is not rusty, rust is not stainless steel, may be a problem with steel.In fact, stainless steel hinge is formed by the surface of a very thin and solid and fine stable rich chromium oxide film (protective film), to prevent oxygen atoms continue to infiltrate, continue to oxidation, and obtain the ability to resist corrosion.

But if, for some reason, the film is constantly being destroyed, oxygen atoms in the air or liquid will constantly infiltrate or iron atoms in the metal will constantly separate out, forming loose iron oxide, and the metal surface will be constantly corroded.Common situations in daily life can be divided into the following categories:
 

1. The surface adhesion of stainless steel hinge contains acid, alkali, salt substances (such as alkali water, stone ash splash), causing local corrosion.

2. Stainless steel hinge surface adhesion organic juice (such as gourd, noodle soup, sputum, etc.), in the case of water and oxygen, organic acid, organic acid for a long time on the metal surface corrosion.

3. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), condensed water will form liquid points of sulfuric acid, nitric acid and acetic acid, causing chemical corrosion.

4 stainless steel hinge surface storage containing other metal elements of dust or metal particles of different kinds of attachment, in the humid air, the attachment and the condensed water between stainless steel, the two connected into a micro battery, triggered the electrochemical reaction, protective film is damaged, said that the electrochemical corrosion.